The Experts below are selected from a list of 1209 Experts worldwide ranked by ideXlab platform
Christopher R. Cheeseman - One of the best experts on this subject based on the ideXlab platform.
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Sustainable infrastructure development through use of calcined excavated waste clay as a supplementary cementitious material
Journal of Cleaner Production, 2017Co-Authors: Ding Zhou, Richard Wang, Mark Tyrer, Hong S. Wong, Christopher R. CheesemanAbstract:Abstract Major infrastructure development projects in London produce large quantities of London clay and use significant volumes of concrete. Portland cement (CEM I) in concrete is normally partially replaced by supplementary cementitious materials such as ground granulated blastfurnace slag or Pulverised Fuel Ash. The supply of supplementary cementitious materials is critical to the production of sustainable concrete. This study has investigated use of waste London clay as a supplementary cementitious material. The optimum calcined clay was produced at 900 °C and concrete made with 30 wt% of CEM I replaced by calcined clay had 28-day strengths greater than control samples. Compressive strengths of concrete containing calcined London clay were similar to concrete containing ground granulated blastfurnace slag and Pulverised Fuel Ash. The production of calcined London clay emits ∼70 kg CO 2 /tonne and this is 91% lower than CEM I. 30 wt% replacement of CEM I by calcined London clay therefore produces concrete with ∼27% lower embodied carbon. London clay can be calcined to form a technically viable supplementary cementitious material and use of this in concrete would enable major civil infrastructure projects to contribute to a circular economy.
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Production of sintered lightweight aggregate using waste Ash and other industrial residues
2011Co-Authors: Christopher R. CheesemanAbstract:This paper reviews research on the use of a range of waste Ashes, including Pulverised Fuel Ash, for the production of lightweight aggregate. Manufacturing lightweight aggregate from Pulverised Fuel Ash has been a highly successful Ash reuse application. The drivers and barriers to the beneficial reuse of waste Ashes are described, and these can be significant, particularly if the Ash is classified as hazardous waste. Research on lightweight aggregate production using Pulverised Fuel Ash, incinerator bottom Ash, sewage sludge Ash and mixed Pulverised Fuel Ash and glass compositions is reviewed. The results demonstrate the importance of rapid firing in developing the micro-structural characteristics necessary for lightweight aggregate production, and the mechanisms occurring during production are outlined.
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production of Pulverised Fuel Ash tiles using conventional ceramic production processes
Advances in Applied Ceramics, 2009Co-Authors: M F Quereda, D Lever, Christopher R. CheesemanAbstract:AbstractThe feasibility of manufacturing sintered ceramic tiles containing a high proportion of Pulverised Fuel Ash (PFA) using conventional ceramic tile processing methods has been investigated at pilot plant scale. From earlier laboratory experiments, a composition containing 92⋅0 wt-%PFA, 5⋅0 wt-% sodium bentonite and 3⋅0 wt-% talc produced good quality small disc samples. The scale-up trials reported here used this same composition and involved deflocculant addition, wet milling, spray drying, pressing and firing, with the behaviour during each processing stage being characterised. Although there were no substantial technical problems associated with forming green tiles, the composition selected needed high levels of deflocculant and produced pressed samples with low green densities, resulting in high shrinkage during firing. The high dependence of shrinkage on temperature caused excessive tile distortion. In addition, sintered samples with less than 2% water absorption exhibited a bloating effect, re...
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characterising the sintering behaviour of Pulverised Fuel Ash using heating stage microscopy
Materials Characterization, 2007Co-Authors: V Adell, Milena Salvo, Monica Ferraris, Christopher R. Cheeseman, Federico SmeacettoAbstract:Heating stage microscopy was used to investigate the sintering behaviour of Pulverised Fuel Ash (PFA). The effect of chemical composition, heating rate, maximum temperature and metal inclusions on densification was studied. It was confirmed that dimensional changes of PFA powder compacts can be controlled by selecting appropriate conditions of sintering temperature and heating rate. It was also found that the sintering behaviour of PFA can be modified with the addition of metal inclusions. The results suggest that development of pores and microstructure of lightweight aggregates (LWA) manufactured from PFA can be controlled by changing the key sintering parameters such as temperature, time and heating rate.
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effect of borate addition on the sintered properties of Pulverised Fuel Ash
Ceramics International, 2007Co-Authors: S G Cook, Christopher R. CheesemanAbstract:The effect of borate addition on the properties of sintered Pulverised Fuel Ash (PFA) has been investigated. PFA from a major coal-fired power station in the UK has been formed into monolithic ceramic samples using dry powder compaction and sintering. Borax pentahydrate (Na2B4O75H2O), anhydrous borax (Na2B4O7) and boric acid (H3BO3) were individually added to the PFA and the effects of firing between 1000 and 1200 8C have been investigated. Physical properties (density, water absorption and linear shrinkage), mechanical properties (bending strength and Vickers hardness), phase composition (X-ray diffraction) and sintered microstructure (scanning electron microscopy) are reported. Milling PFA containing 8% (by weight) of borax pentahydrate, to an average particle size of 7.25 mm and sintering at 1130 8C for 1 h, produces ceramics with properties comparable to those of commercial unglazed ceramic wall and floor tiles. The results indicate that PFA could be used to produce commercial ceramics using an economic manufacturing process, although current formulations display excessive shrinkage. # 2006 Elsevier Ltd and Techna Group S.r.l. All rights reserved.
Leon Black - One of the best experts on this subject based on the ideXlab platform.
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effect of synthesis parameters on the performance of alkali activated non conformant en 450 Pulverised Fuel Ash
Construction and Building Materials, 2016Co-Authors: S Aduamankwah, David E Searle, Jamal M. Khatib, Leon BlackAbstract:The fly Ash reported in this paper is coarser than conventional Pulverised Fuel Ash (PFA), with loss on ignition (LOI) exceeding 10.8%. Consequently, it is precluded from being used as a supplementary cementitious material (SCM) according to EN 450 and disposed in landfills. Alkali-activation of such PFAs is considered here. Three concentrations of sodium hydroxide (NaOH) were separately blended with water glass at different ratios to modify the silica modulus. Heat of reaction, setting time, compressive strength and drying shrinkage were investigated as a function of activator composition. Specimens were either cured at room temperature or hydro-thermally treated at 75 °C for five hours. The results show that by optimizing the activator composition, a binder with a 28 day compressive strength of 25 MPa can be synthesised from such PFAs even at room temperature. Among the activator parameters, the alkali content was observed to be most influential.
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alkali activated solidification stabilisation of air pollution control residues and co fired Pulverised Fuel Ash
Journal of Hazardous Materials, 2011Co-Authors: R Shirley, Leon BlackAbstract:Abstract This paper examines the potential treatment by solidification/stabilisation (S/S) of air pollution control (APC) residues using only waste materials otherwise bound for disposal, namely a Pulverised Fuel Ash (PFA) from a co-fired power station and a waste caustic solution. The use of waste materials to stabilise hazardous wastes in order to meet waste acceptance criteria (WAC) would offer an economical and efficient method for reducing the environmental impact of the hazardous waste. The potential is examined against leach limits for chlorides, sulphates and total dissolved solids, and compressive strength performance described in the WAC for stable non-reactive (SNR) hazardous waste landfill cells in England and Wales. The work demonstrates some potential for the treatment, including suitable compressive strengths to meet regulatory limits. Monolithic leach results showed good encapsulation compared to previous work using a more traditional cement binder. However, consistent with previous work, SNR WAC for chlorides was not met, suggesting the need for a wAshing stage. The potential problems of using a non-EN450 PFA for S/S applications were also highlighted, as well as experimental results which demonstrate the effect of ionic interactions on the mobility of phases during regulatory leach testing.
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Alkali activated solidification/stabilisation of air pollution control residues and co-fired Pulverised Fuel Ash.
Journal of Hazardous Materials, 2011Co-Authors: R Shirley, Leon BlackAbstract:Abstract This paper examines the potential treatment by solidification/stabilisation (S/S) of air pollution control (APC) residues using only waste materials otherwise bound for disposal, namely a Pulverised Fuel Ash (PFA) from a co-fired power station and a waste caustic solution. The use of waste materials to stabilise hazardous wastes in order to meet waste acceptance criteria (WAC) would offer an economical and efficient method for reducing the environmental impact of the hazardous waste. The potential is examined against leach limits for chlorides, sulphates and total dissolved solids, and compressive strength performance described in the WAC for stable non-reactive (SNR) hazardous waste landfill cells in England and Wales. The work demonstrates some potential for the treatment, including suitable compressive strengths to meet regulatory limits. Monolithic leach results showed good encapsulation compared to previous work using a more traditional cement binder. However, consistent with previous work, SNR WAC for chlorides was not met, suggesting the need for a wAshing stage. The potential problems of using a non-EN450 PFA for S/S applications were also highlighted, as well as experimental results which demonstrate the effect of ionic interactions on the mobility of phases during regulatory leach testing.
V Adell - One of the best experts on this subject based on the ideXlab platform.
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comparison of rapid and slow sintered Pulverised Fuel Ash
Fuel, 2008Co-Authors: V Adell, A. Doel, C R Cheeseman, A Beattie, Aldo R BoccacciniAbstract:Abstract This study has investigated the properties of sintered PFA using conventional (20 °C/min) and rapid heating rates. Rapid heating was achieved by directly placing pressed PFA samples into a furnace preset at the sintering temperature. Slow sintered PFA samples show an increase in shrinkage and fired density and a reduction in water absorption as the sintering temperature increases, with maximum density obtained at around 1250 °C. At higher temperatures samples show a bloating effect associated with the enlargement of closed porosity. This peak in density is not observed in rapidly sintered PFA. Rapid sintering at temperatures between 1150 °C and 1300 °C resulted in constant values of shrinkage (6.5%), fired density (1.4 g/cm 3 ) and water absorption (15%). During rapid sintering the residual carbon in the PFA is present in the sample at the sintering temperature whereas conventional sintering removes the carbon at lower temperatures before sintering occurs. Rapid sintering also retains significant carbon in the core of the sintered sample. This carbon is believed to act as rigid inclusions that inhibit PFA sintering, limiting shrinkage and densification. Rapid sintering is associated with black coring which is also characteristic in lightweight aggregate manufactured from PFA sintered on a sinter strand. The rapid heating rate experienced by PFA pellets on a sinter strand and the associated inhibition of sintering by carbon is essential for producing sintered PFA products with properties appropriate for use as lightweight aggregate.
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characterising the sintering behaviour of Pulverised Fuel Ash using heating stage microscopy
Materials Characterization, 2007Co-Authors: V Adell, Milena Salvo, Monica Ferraris, Christopher R. Cheeseman, Federico SmeacettoAbstract:Heating stage microscopy was used to investigate the sintering behaviour of Pulverised Fuel Ash (PFA). The effect of chemical composition, heating rate, maximum temperature and metal inclusions on densification was studied. It was confirmed that dimensional changes of PFA powder compacts can be controlled by selecting appropriate conditions of sintering temperature and heating rate. It was also found that the sintering behaviour of PFA can be modified with the addition of metal inclusions. The results suggest that development of pores and microstructure of lightweight aggregates (LWA) manufactured from PFA can be controlled by changing the key sintering parameters such as temperature, time and heating rate.
S G Cook - One of the best experts on this subject based on the ideXlab platform.
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effect of borate addition on the sintered properties of Pulverised Fuel Ash
Ceramics International, 2007Co-Authors: S G Cook, Christopher R. CheesemanAbstract:The effect of borate addition on the properties of sintered Pulverised Fuel Ash (PFA) has been investigated. PFA from a major coal-fired power station in the UK has been formed into monolithic ceramic samples using dry powder compaction and sintering. Borax pentahydrate (Na2B4O75H2O), anhydrous borax (Na2B4O7) and boric acid (H3BO3) were individually added to the PFA and the effects of firing between 1000 and 1200 8C have been investigated. Physical properties (density, water absorption and linear shrinkage), mechanical properties (bending strength and Vickers hardness), phase composition (X-ray diffraction) and sintered microstructure (scanning electron microscopy) are reported. Milling PFA containing 8% (by weight) of borax pentahydrate, to an average particle size of 7.25 mm and sintering at 1130 8C for 1 h, produces ceramics with properties comparable to those of commercial unglazed ceramic wall and floor tiles. The results indicate that PFA could be used to produce commercial ceramics using an economic manufacturing process, although current formulations display excessive shrinkage. # 2006 Elsevier Ltd and Techna Group S.r.l. All rights reserved.
Ding Zhou - One of the best experts on this subject based on the ideXlab platform.
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Sustainable infrastructure development through use of calcined excavated waste clay as a supplementary cementitious material
Journal of Cleaner Production, 2017Co-Authors: Ding Zhou, Richard Wang, Mark Tyrer, Hong S. Wong, Christopher R. CheesemanAbstract:Abstract Major infrastructure development projects in London produce large quantities of London clay and use significant volumes of concrete. Portland cement (CEM I) in concrete is normally partially replaced by supplementary cementitious materials such as ground granulated blastfurnace slag or Pulverised Fuel Ash. The supply of supplementary cementitious materials is critical to the production of sustainable concrete. This study has investigated use of waste London clay as a supplementary cementitious material. The optimum calcined clay was produced at 900 °C and concrete made with 30 wt% of CEM I replaced by calcined clay had 28-day strengths greater than control samples. Compressive strengths of concrete containing calcined London clay were similar to concrete containing ground granulated blastfurnace slag and Pulverised Fuel Ash. The production of calcined London clay emits ∼70 kg CO 2 /tonne and this is 91% lower than CEM I. 30 wt% replacement of CEM I by calcined London clay therefore produces concrete with ∼27% lower embodied carbon. London clay can be calcined to form a technically viable supplementary cementitious material and use of this in concrete would enable major civil infrastructure projects to contribute to a circular economy.
